title: The interplay of HuR and miR-3134 in regulation of AU rich transcriptome.
abstract: MicroRNAs and AU Rich element (ARE)-mediated degradation of transcripts are thought to be two independent means of gene regulation at the post-transcriptional level. However, since their site of action is the same (3'UTR of mRNA), there exists a high probability that specific miRNAs may bind to AREs and, thus, interact with ARE-binding proteins (ARE-BPs) to regulate transcript levels. In this study, we have characterized AREs as potential targets of hsa-miR-3134. An analysis of the global gene expression profile of breast cancer cell line MCF7 overexpressing miR-3134 revealed the presence of at least one AUUUA element in the 3'-UTRs of 63% of miR-3134 regulated protein coding genes. Quantitative RT-PCR or 3'UTR luciferase assays show that miR-3134 mediates an up to 4-8-fold increase in the levels of ARE bearing transcripts-SOX9, VEGFA, and EGFR, while mutated miR-3134 shows a decreased effect. The miR-3134-mediated increase in transcript levels was unaffected by treatment with transcription inhibitor (actinomycin D), indicating that miR-3134 enhances transcript stability. To investigate a possible interplay between miR-3134 and a prototype ARE-BP, HuR, we compared their overexpression transcriptome profiles. Interestingly, up to 80% of miR-3134-regulated genes were also regulated by HuR. Overexpression studies of HuR alone or in combination with miR-3134 shows that wt miR-3134 but not a mutated miR-3134 promotes stabilization of HuR-regulated transcripts SOX9, VEGFA, and EGFR as confirmed by qRT-PCR or RNA-immunoprecipitation experiments. Overall, this report suggests that collaboration between ARE-binding microRNAs and ARE-binding proteins could be a general mechanism of 3'-UTR mediated regulation of gene expression in human cells.
authors.affiliation: Department of Biochemical Engineering and Biotechnology; Indian Institute of Technology; Delhi, India.
authors.forename: Shivani
authors.initials: S
authors.lastname: Sharma
authors.forename: Suneer
authors.initials: S
authors.lastname: Verma
authors.forename: Madavan
authors.initials: M
authors.lastname: Vasudevan
authors.forename: Subhasis
authors.initials: S
authors.lastname: Samanta
authors.forename: Jitendra K
authors.initials: JK
authors.lastname: Thakur
authors.forename: Ritu
authors.initials: R
authors.lastname: Kulshreshtha
mesh_terms: D020413:3' Untranslated Regions; D063307:AU Rich Elements; D003609:Dactinomycin / Q000494:pharmacology; D051959:ELAV Proteins / Q000235:genetics / Q000378:metabolism*; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism; D005260:Female; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D061986:MCF-7 Cells; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism*; D055758:SOX9 Transcription Factor / Q000235:genetics / Q000378:metabolism; D059467:Transcriptome / Q000235:genetics / Q000502:physiology*; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism
chemical_list: D020413:3' Untranslated Regions; D051959:ELAV Proteins; D035683:MicroRNAs; D055758:SOX9 Transcription Factor; C527932:SOX9 protein, human; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D003609:Dactinomycin; C512478:EGFR protein, human; D066246:ErbB Receptors
keywords: AU rich elements; Breast cancer; HuR; MicroRNA; miR-3134